Endothermic and Exothermic Reactions: What’s the Difference?

images (33)Endothermic and exothermic may sound similar but are complete polar opposites of each other. Depending on what chemicals and or conditions are in a certain system, it will be either endothermic or exothermic. Although we may not think about it, endothermic and exothermic are always happening in our everyday lives.

Coming from the greek roots of “exo” meaning outside and “therm” meaning heat, exothermic reactions are reactions that release heat from its system into its immediate surroundings. When exothermic reactions occur, the immediate surroundings of the reactions gain energy becoming hot while the system itself loses energy becoming cold. This is the case because when the reaction occurs, heat is the product so if the system releases energy, so the immediate surrounding area will be hot. When exothermic reactions occur, the reactants yield the products plus heat. In an exothermic reactions the reactants have more energy that the products meaning the We see reactions that are exothermic in our everyday life, like something as obvious as a hot compression pad but there are many other everyday things we encounter. The flame of a candle is exothermic because the energy is being released into the immediate surrounding while the system loses energy. Other examples of exothermic reactions are the formation of ice, mixing water with acids, and nuclear fission. Exothermic reactions are very useful being that the methane combustion in our gas stoves, the combustion of the gas in our cars, and the use of dynamite that mines our coal, are all exothermic reactions. Also, cellular respiration is exothermic.

Endothermic reactions, being the complete opposite of exothermic reactions, comes from the greek roots of “endo” meaning within and “therm” meaning heat. Endothermic reactions absorb heat from the immediate surroundings into the system making the immediate surroundings colder because of the lesser amount of energy previously there. This is the case because when the reaction occurs, energy is needed to make the product so it takes the surrounding energy making the surroundings cold. In endothermic reactions, the reactants and energy yield the products. Endothermic reactions like baking bread, the production of sugar in photosynthesis, and cooking an egg are all things that we experience in our everyday lives and are very important. The most important endothermic reaction is the evaporation of water which we use to sweat which is a way to maintain homeostasis and not pass out and die. Also, obviously cold packs are endothermic being that when mixing the two chemicals in the bag, it becomes cold.